Some people are turning to e-cigarettes in the hope that they are a less life-threatening addiction, but Dr White says their safety cannot be guaranteed – for users or people nearby.

"Regardless of the threats to health that second-hand vapour could pose, many bystanders find it unpleasant and simply don't want to breathe in pollutants from someone else's e-cigarette," she points out.

"Most people would likely prefer to breathe in fresh air, so it's probably courteous to refrain from vaping in public places, particularly where smoking conventional cigarettes is not permitted."

As for those doing the vaping, Dr White cautions against assuming they're a healthy alternative to smoking.

"Currently there is insufficient evidence to support the use of e-cigarettes as a quitting aid," she says.

"Many e-cigarettes labelled as not containing nicotine, an addictive drug, have actually been found to contain nicotine when tested independently. So there are some real concerns about consumer safety standards."

At present, e-cigarettes can be sold in Australia provided they don't contain nicotine and don't make therapeutic claims to aid quitting smoking, although some people import nicotine-containing e-cigarettes from overseas.

"Quit Victoria has concerns about the potential short and long-term health effects of e-cigarettes," Dr White says.

"Legislation is urgently needed to address this emerging problem including banning the retail sale of novelty non-nicotine e-cigarettes, extending smoke-free laws to cover all e-cigarette use and banning advertising and promotion of all e-cigarettes."